Fuel pump or fuel pressure regulator?

[ggrant]

Hey guys need help here..call me crazy but I am restoring my 99 4runner Limited 4x4 with 330k on it....it is family.

Here's the issue: at cold start it has a rough idle for about 15-20 seconds that then goes away. I have also noticed a very "rich" gas smell also when it does this. Also when accelerating onto the freeway it acts as if it is gasping for fuel but not getting it. Just had the the heads rebuilt and all seals and gaskets replaced this winter due to a burnt valve on #4. 2 cylinders have 150psi and the other 4 are at 125. Darn near everything has been replaced over the last 12-18 months. Once it is warmed up the rough idle goes away at start up. Any help would be greatly appreciated. THANKS!!!!!

 

[blanchard7684]

A sensor is not reading right and telling the ECU to run way rich or way lean.

An injector may be stuck as well.

Pull plugs and check for excessive richness.

Or get a code reader and check for any codes.

Possible list of sensors that can do this:

MAF, Eng. coolant, intake air temp sensor.

When cold your ecu "ignores" feedback from o2 until certain engine temp. don't think its o2 sensor related.

You can also get a fuel pressure test to rule out fuel pump just to be certain. but most fuel pumps would have insufficient flow at all engine conditions.

 

[Spktyr]

I second that - get a code reader and pull codes. If that doesn't work get a Wifi OBD2 adapter (~$20) to connect to a computer or phone/tablet so you can see things like fuel trim in real time and perform better diagnosis.

 

[nevada]

Hey guys need help here..call me crazy but I am restoring my 99 4runner Limited 4x4 with 330k on it....it is family.

Here's the issue: at cold start it has a rough idle for about 15-20 seconds that then goes away. I have also noticed a very "rich" gas smell also when it does this. Also when accelerating onto the freeway it acts as if it is gasping for fuel but not getting it. Just had the the heads rebuilt and all seals and gaskets replaced this winter due to a burnt valve on #4. 2 cylinders have 150psi and the other 4 are at 125. Darn near everything has been replaced over the last 12-18 months. Once it is warmed up the rough idle goes away at start up. Any help would be greatly appreciated. THANKS!!!!!

is it using any coolant? do you ever have to add any?

 

[Cookie1498]

2002 limited. Good fuel pressure out of tank (42-48psi). Engine starts and shuts off within a few seconds. Regulator or injectors? Or is there something else stopping fuel flow?